Conventionally, a speech interactive system has been known which carries out conversation between a system and a user with speech (see Patent Document 1, for example). The speech interactive system includes a speaker for outputting system side speech to a user; a microphone for converting speech the user utters in response to the system side speech output from the speaker to a speech signal; a speech recognizing section for recognizing the speech input to the microphone; an utterance timing detecting section for detecting utterance timing on the basis of the speech signal obtained by converting the speech through the microphone and a response speech signal from a response generating section; a skill level deciding section for deciding a skill level of the speech interaction of the user using the utterance timing; and a speech output altering section for altering an output content of the system side speech in accordance with the skill level decided by the skill level deciding section.
Generally, in the speech recognizing apparatus, the speech recognition is decided only by acoustic characteristics of the speech the user utters. For example, the duration from the time the system enters into a recognizable mode when the user pushes down a recognition start button to the time the user actually starts his or her utterance (referred to as “utterance timing” from now on) does not affect the recognition result.    Patent Document 1: Japanese Patent Laid-Open No. 2004-333543.
The speech interactive system disclosed in the foregoing Patent Document 1 is configured in such a manner as to decide the skill level of the speech interaction on the basis of the utterance timing, frequency of use and utterance speed, and to carry out the speech recognition considering the skill level. However, the skill level is applied only to the output alteration of the system side speech (guidance speech), and does not have a direct effect on the recognition result. Accordingly, there is a problem of bringing about misidentification depending on the utterance timing of the user.
The present invention is implemented to solve the foregoing problem. Therefore it is an object of the present invention to provide a speech recognizing apparatus mounted on a vehicle capable of providing a user with appropriate information about the speech recognition result in accordance with the user utterance timing.